Dry pipe-valve.



Patented July 23, 1912.

G. I. ROCKWOOD.

DRY PIPE VALVE. APPLIOATION FILED JUNE 12, 1909,

O m a m Q 4 Am /A m Z 7 a 9 i 3 s K V w H W 5 GEORGE I. ROCKWOOD, OF WORCESTER, MASSACHUSETTS.

DRY PIPE-VALVE.

Specification of Letters Patent.

Patented July 23, 1912.

Application filed June 12, 1909. Serial No. 501,795.

To all whom it may concern:

Be it knownthat I, GEORGE I. RooKwooo, a citizen of the United States, residing at lVorcester, in the county of Worceste'r and Commonwealth of Massachusetts, have invented a new and useful Improvement in Dry Pipe-Valves, of which the following is a specification, accompanied by drawings forming a part of the same, in which Figure 1 represents a side elevation in central sectional view of a dry pipe valve embodying my present invention, and Fig. 2 is 'a plan view of the gravity latchfor locking the valve in a raised position.

Similar reference characters refer to similar parts in the differentfigures.

My present invention relates to a dry pipe valve-comprising a rocking arm or lever carrying a valve, arranged to close a passage tothe flow of water under pressure, said valve presenting different areas of pressure on opposite sides, whereby a small pressure against the side of greater area will resist a greater pressure against the side of lesser Zll'eil.

Dry pipe valves of this class are now in common use, and my present invention relates particularly to the application of a gravity latch to hold the valve in araised or partially raised position.

Referring to the accompanying drawings, 1 denotes'a shell or casing havingan inlet passage 2 and an outlet passage 3 for the flow of water therethrough. The inlet passage 2 is closed .by a valve 4 which rests upon a valve seat5. The outer edge of the valve 4: rests upon an annular valve seat 6. As the area-of the'va'lve within the valve seat 6 is much greater than the area of the valve within the valve seat 5, a downwardpressure'upon the upper surface of the valve will be capable of resisting a greater pressure within the inlet passage 2 applied to the under side of the valve. Awater supply under pressure will, therefore, be held by the valve 4 by the application of a lesser pressure upon the upper surface of the valve. Devices of this class are'employed in automatic sprinkler systems and, whenever the pressure above the valve is relieved by the opening of a sprinkler, the pressure of the water supply through the inlet passage 2 forcibly raises the valve and allows the current of water to pass through the shell 1 and outlet passage 3. The valve 4 is pivotally connected by a pin 7 w1th the free end of a lever 8, which is pivoted within the casing 1 upon a pin 9. The lever 8 is provided with a counterweight 10, and arranged upon the arc of a circle concentric with the pivotal pin 9 are the ratchet teeth 11 and 12. Passing through the casing 1 is a pin 13, upon which is pivotally hung a gravity pawl 14 by means of lugs 15, having holes 16 considerably larger than the pivotal pin in order to allou free play to the gravity pawl upon the pin 13. When the v valve 4 is closed, the free end of the gravity pawl rests upon the .tip of the tooth l1 and the opposite end of the pawl bears against a shoulder 17 formed in' the casing 1. As the lever 8 is rocked by the lifting of the valve 4, the free end of the pawl will drop behind the tooth 11 preventing the return of the valve and, if the liftingmovement is continued, the pawl will finally drop behind the tooth 12 and hold the valve in a partiallyv raised position by its engagement with a tooth of the lever 8. If the force of the water through the inlet passage 2 raises the valve to the limit of its upward movement, the counterweight will have been lowered sufficiently to hold the valve in its raised position, but any partial movement of the valve sufficient to allow either of the teeth 11 or 12 to be caught by the gravity pawl 14 will prevent the valve from closing.

The pressure of either of the teeth 11 or.12

against the free end of the pawl will be resisted by the shoulder 17, relieving the pivotal pin 13 from pressure.

The free end of. the pawl 14 is curved as site end of the pawl is curved at 19.,.=preshown at 18, presentinga curved surface to contact with the teeth 11 and 12; The oppo senting a curved surface tojcontact with the";

, shoulder 17, so that the straight contacting surfaces of the teeth 11 and 12 will strike the curved surface 18 at a single tangential point, notwithstanding any lateral angular displacement of the pawl. straight shoulder 17 will contact with the curved surface 19 at a single tangential point. The line of pressure, therefore, will lie between the single-points of contact on the opposite curved surfaces of the pawl. The pivotal pin 13 may be inserted loosely through the holes 20 in the casing 1 and the holes closed by screws 21.

Between the casing 1 and the sides of the pawl I insert loose washers 22 of a noncorrosive material, which obviates the lia- Likewise the bility of iinpeding the free action 0f the pawl.

I claim, v

1. A dry pipe valve, comprising a case having inlet and outlet openings, a'valve closing said inlet opening, a rocking lever carrying said valve and having a projecting tooth, a pin through said case above said lever, a pawl pivotally hung on said pin by lugs having holes larger than said pin, said pawl approximately the width of said'lever and arranged to engage said tooth by gravity when said lever is rocked.

2. In a dry pipe valve, a case having inlet I and outlet openings, a'pivoted valve for closing said inlet opening, a gravity pawl loosely pivoted at one end within said case for holding said valve in a raised position, and ashoulder in said case for engaging the pivoted end of said pawl.

having a projection for a retaining pawl, a

retaining pawl loosely pivoted at one end within said case and arranged to engage said projection by gravity, and an abutting member onsaidcase arranged to resist the end thrust upon said pawl.

4. In a dry ipe valve, a case, a rocking valve lever plvoted within said case, a

gravity pawl loosely pivoted at one end within said case, and a pawl abutting men 1 her on said case to resist the thrust of sald "pawl, said pawl having rounded contacting ends.

GEORGE I. ROCKWOOD.-

Witnesses PENELOPE CoMBERBAoH, NELLIE WHALEN. 

